Microphase-separated Structure of Ultrathin Polyurethane Films

We firstly observed the effect of film thickness on a microphase-separated structure of polyurethane at the ultrathin states. The interdomain spacing of domains decreased with decreasing film thickness due simply to the reduction of the space for domains.Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Invited Lectur

Direct Observation of Microphase-separated Structure of Polyurethane by Temperature Dependent Atomic Force Microscopy

Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

Characterization of Functionally Graded Polyurethane Elastomers

Functionally graded polyurethane elastomers (FGPUEs) were prepared by poly(oxytretamythylene) glycol (PTMG) and 4, 4\u27-diphenylmethane diisocyanate (MDI) with two molds fixed at different temperature. Effect of temperature gradient on the molecular aggregation state and mechanical properties were studied by differential scanning calorimetry (DSC), polarized optical microscope (POM), Fourier transform infrared spectroscopy (FT-IR) and pulsed nuclear magnetic resonance (NMR). Spherulite size of FGPUEs depended on the temperature gradient. Spherulite content of FGPUEs decreased from the low temperature side to the higher temperature side and spherulite size became greater toward the higher one. The glass transition increased from the lower temperature side to the higher temperature side. This was associated with the strong phase separation of the lower temperature side

Synthesis and Characterization of Rotaxane Closslinked Polyurethanes

Three polyurethanes (PU0, PU11 and PU33) where azobis(dibenzo-24-crown-8 ether) 1 acts as a crosslink point with a [3]rotaxane structure except PU0 were synthesized and characterized by H^^1 NMR and ATR-FT-IR spectroscopies, and DSC.Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

Synthesis and properties of highly hydrophilic polyurethane based on diisocyanate with ether group

Highly hydrophilic polyurethane elastomers (PUEs) were synthesized from 1,2-bis(isocyanate) ethoxyethane (TEGDI), poly(ethylene oxide-co-propylene oxide) copolyol (EOPO) and 1,4-butane diol/1,1,1-trimethylol propane (75/25) (wt/wt) by a prepolymer method. 4,4′-Diphenylmethane diisocyanate (MDI)-based PUEs were synthesized as a control as well. Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) measurements revealed that the degree of microphase separation of the TEGDI-based PUEs was much weaker than for the MDI-based PUEs. Young\u27s modulus and elongation at break of the TEGDI-based PUEs were quite lower and larger than for the MDI-based PUEs, respectively. This is due to quite weak cohesion force of the hard segment chains in the TEGDI-based PUEs. The degree of swelling of the TEGDI-based PUEs was five times larger than for the MDI-based one. This is associated with the hydrophilic nature of TEGDI and weak cohesion force in the TEGDI-based PUEs

Chain and mirophase-separated structures of ultrathin polyurethane films

Measurements are presented how chain and microphase-separated structures of ultrathin polyurethane (PU) films are controlled by the thickness. The film thickness is varied by a solution concentration for spin coating. The systems are PUs prepared from commercial raw materials. Fourier-transform infrared spectroscopic measurement revealed that the degree of hydrogen bonding among hard segment chains decreased and increased with decreasing film thickness for strong and weak microphase separation systems, respectively. The microphase-separated structure, which is formed from hard segment domains and a surrounding soft segment matrix, were observed by atomic force microscopy. The size of hard segment domains decreased with decreasing film thickness, and possibility of specific orientation of the hard segment chains was exhibited for both systems. These results are due to decreasing space for the formation of the microphase-separated structure.IUMRS-ICA 2008 Symposium Sessions X and Y. Soft Matter Science, 9-13 December, Nagoya, Japa

Molecular Mobility of Soft Segment of Polyurethane Elastomers under Elongation

Abstract. In this study, we investigated molecular mobility of a soft segment in the poly(oxypropylene) glycol (PPG), 4,4\u27-diphenylmethane diisocyanate (MDI) and 1,4-butane diol (BD)-based polyurethane elastomers (PUE) with and without elongation by dynamic viscoelastic property measurement and pulse nuclear magnetic resonance (NMR) measurement. The peak position of the loss tangent (tand) curves shifted to the lower temperature region with increasing elongation. In the pulse NMR measurement, the long spin-spin relaxation time {T2) component appeared at -18.0 (e = 0) and -26.0 °C (e =1.5), respectively, with increasing temperature. Since this temperature seems to be related to the glass transition temperature (Jg) of the soft segment in the PUE, it is likely to consider that the Tg decreased with increasing strain. These results might be attributed that the size of cooperative motion during the glass transition decrease due to the orientation of the soft segment, and the soft segment phase approach to a pure phase on account of the extraction of the hard segment from the soft segment phase.THE XV INTERNATIONAL CONGRESS ON RHEOLOGY: The Society of Rheology 80th Annual Meeting : Monterey (California), 3?8 August 200

Reactions of (polypyrazolylborato)(benzonitrile)rutheniums with terminal alkynes: Reactivity changeover by triethylamine toward arylalkyne polymerization or formation of (arylmethyl)(carbonyl) complexes

Reactions of (κ 3-polypyrazolylborato)(benzonitrile) rutheniums [RuCl{B(4-Ypz) 4}(PhCN) 2] {4-Ypz; 4-bromo-1-pyrazolyl (Y = Br) and 1-pyrazolyl (Y = H) groups} with terminal alkynes were studied. For the reactions with arylalkynes HC≡C(aryl) in the presence of NEt 3, (arylmethyl)(carbonyl)rutheniums [Ru{CH 2(aryl)}{B(4-Ypz) 4}(CO)(PhCN)] were yielded, indicating alkyne C≡C bond cleavage, whereas in the absence of NEt 3, arylalkyne polymerization proceeded instead of the (arylmethyl)ruthenium formation. Reasonably attributed reaction mechanism shows significant role of the vinylidene intermediates "Ru=C=CH(aryl)"